The invention concerns an In-the-ear hearing aid for persons with impaired hearing which contains microphone, amplifier, earphone, battery and a connector for an ear adapter.
In the development of hearing aids, the general trend was away from the "box" type unit towards units which can be worn behind the ear, in the ear, or combined with or integrated in frames of spectacles. During all of these developments, the increasing miniaturization of components was always utilized to improve and/or miniaturize the devices in many ways, but there was always the feeling that this is a prosthetic device which ought to be kept hidden.
More recent developments led to hearing aids which are so small that the complete device can be worn in the cavity (concha) which is formed by the various parts of the external ear.
The first devices of this type were manufactured by taking a casting of the external ear to form a hollow, so-called ear mold which matched the ear of the future wearer and which was equipped with a sound channel which projected slightly into the auditory channel. After this, the components of the device were installed in this ear mold which was then fitted with a cover. Such individual production made manufacture both time-consuming and costly.
It is already known that the manufacture of simple and cheap hearing aids in the external ear can be achieved by installing the components in a housing which is shaped such that it fits reasonably well into the concha of a normal ear. This housing device is then fitted into a recess in an ear casting which can either be made individually or can be a standard version which approximately fits most ears. Hearing aids of this type naturally have an unpleasant apperance and it is necessary to manufacture two different types for left and right ears.
Such a device can be used by the hearing aid specialist only with certain restrictions.